Friday, May 7, 2010

Beaver

Alright, I had a different animal planned for today, but then a news story popped up that I simply could not ignore....

World's largest beaver dam. Located in a remote, basically inaccessible area of Alberta, Canada, this thing is almost 3,000 feet long and has likely been under construction for 40 years by multiple beaver families and generations. (Alberta is interestingly also the home of a 15 foot tall roadside beaver attraction!)


Beavers had a guest role in one of my posts last week, which mentioned their importance to local ecosystems. Beavers build dams for food storage and protection, but there are several valuable side effects that go along with them just trying to get away from some coyotes. These dams help to prevent erosion, help develop new wetlands, mitigate the damage cause by floods, provide spawning sites for salmon and help to adsorb excess sediments. These are only a few of the long and short terms benefits provided by beaver dams, and its no wonder other species have disappeared following beaver extinction in a certain area. Their homes hold a habitat together... provided it is the correct type of habitat. Beavers were introduced to an Argentinian island in the 1940's for fur farming purposes, but because the trees there were not meant to have submerged roots, they began to rot and the original habitat flooded and caused serious damage over time.


There are two species of beaver, the North American (Castor canadensis) and the European (Castor fiber). They have some differences in their physical characteristics, and they are not genetically compatible between species, but they are fairly similar in size, ranking as #3 and #2 respectively for the largest rodents in the world. (Capybara wins #1) It is not uncommon for them to hit 50 lbs! 


Both species once had vast habitat ranges through their respective continents, but where hunted to near extinction for their pelts and for a medicinal secretion called castoreum. Efforts to reintroduce them have been happening around the world.


image from Beavers in England

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